Air valve carburetor

ABSTRACT

An air valve carburetor has an air valve secured to an air valve shaft for pivotal rotation therewith; a pair of fuel metering valve assemblies are respectively situated between the carburetor fuel bowl means and the respective fuel nozzles situated within first and second air induction passages formed in the carburetor body; and a pair of cam assemblies carried by the air valve shaft are adjustable with respect to each other and with respect to the air valve and air valve shaft; the cam assemblies are operatively connected to and effective for variably positioning valving members of the fuel metering valve assemblies in accordance with the positions assumed by the air valve during engine operation.

United States Patent 11 1 3,695,589 Lamore 1 1 Oct. 3, 1972 [54] AIR VALVE CARBURETOR Primary Examiner-Tim R. Miles [72] Inventor: Herbert T. Lamore, Detroit. Mich. Attorney-Walter Potomka [73 Assignee: Holley Carburetor Company, War- [57] ABSTRACT ren, Mich. 1

An air valve carburetor has an air valve secured to an [22] Filed: March 2, 1970 air valve shaft for pivotal rotation therewith; a pair of fuel metering valve assemblies are respectively situ- [211 Appl' 15427 ated between the carburetor fuel bowl means and the respective fuel nozzles situated within first and second [52] US. Cl. ..261/23 A, 261/ A air induction passages formed in the carburetor body; [51] Int. Cl ..F02m 11/02 and a pair of cam assemblies carried by the air valve [58] Field Of Search ..26l/23 A, 50A shaft are adjustable with respect to each other and with respect to the air valve and air valve shaft; the [56] References Cited cam assemblies are operatively connected to and effective for variably positioning valving members of the UNITED STATES PATENTS fuel metering valve assemblies in accordance with the 3,279,767 10/1966 Stoltman ..26l/50 A pos tions assum d y h a valve u ng ng ne ,974 8/1966 Braun et al. ..26l/5O A peration. 2,099,553 11/1937 Atkins ..26l/50A 2,970,822 2/1961 Ernest ..261/23 A 7 Clams 5 Draw'ng 3,188,062 6/1965 Reid et al ..261/23 A 3,485,482 12/1969 Fuchs ..26l/23 A I 8 32, f a {9 2% 721 I 80 (86 i is a [95 a; 524 1 96 24 0 Oi as 1 :L/J 2: 4 4 I $1 l Q5 3': Qi-

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ATTURNEY AIR VALVE CARBURETOR BACKGROUND OF THE INVENTION Air valve carburetors, as generally well known inthe art, employ an air valve which is responsive to the volume of air flowing through the air inlet of the engine to in effect measure the volume rate of such air flow. The air valve is usually connected to a fuel metering valve whereby fuel flow to the engine will be regulated in accordance with the air flow and thus a proper mixture of air and fuel may be delivered to the engine.

One of the problems encountered by the prior art air valve carburetors arose in connection with carburetor structures having two or more induction passages which employed a single common air valve but separate fuel discharge nozzles for the respective induction passages. In such structures it was found that employing a single fuel metering valve assembly connected to the air valve for supplying metered fuel to the fuel discharge nozzles collectively resulted in improper fuel-air ratios in at least certain of the induction passages because of the flow dynamics of the fuel and air conduits or passages.

Accordingly, the prior art attempted to solve this by providing a separate fuel metering valve assembly connected to the air valve for each of the induction passages of the carburetor structure. However, problems were again encountered resulting from the dimensional tolerances necessary during machining and assembly. That is because of a stack-up of tolerances, it was often the case that a proper position of the valving or fuel metering rods of the fuel metering valve assemblies could not be achieved for a particular related position of the air valve connected thereto. The prior art sought to solve this problem by providing a single cam-like member carried by the air valve which could be adjustably positioned so as to vary the position of both or all of the fuel metering valve assembly metering rods, collectively, with respect to the air valve.

However, a major problem still exists that is, it has been discovered that, for example, in a carburetor having first and second induction passages containing an air valve and having first and second fuel metering valve assemblies respectively feeding first and second fuel nozzles in the first and second induction passages, the first of the fuel metering valve assemblies may be providing the desired fuel flow rate to the engine with respect to the position assumed by the air valve while the second fuel metering valve assembly may be providing either an insufficient or an excessive rate of fuel flow. Therefore, in such situations, which often happen, it is impossible to correct the metered rate of fuel flow from the second fuel metering valve, by employing the single cam of the prior art Without deleteriously effecting the performance of the firstfuel metering valve assembly.

Accordingly, the invention as disclosed and described herein is concerned with the solution of the above as well as other related problems.

SUMMARY OFTHE INVENTION According to the invention, an air valve comprises a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the total volume rate of air flow through said first and second induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging meteredfuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connectedto said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, and second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve.

Various general and specific objects and advantages of the invention will become apparent when reference is made to the following detailed description considered in conjunction with the accompanying drawings. I

DESCRIPTION OF THE DRAWINGS In the drawings wherein, for purposes of clarity, certain details may be omitted from oneor more views:

FIG. 1 is a top plan view of an air valve carburetor, with portions thereof broken away and in cross-section, constructed in accordance with the invention;

FIG. 2 is a side elevational view of the carburetor of FIG. 1;

FIG. 3 is an enlarged fragmentary cross-sectional view taken generally on the plane of line 3-3 of FIG. 1 and looking inthe direction of the arrows;

FIG. 4 is an enlarged view, of a portion of the structure shown in FIG. 3, taken generally on the plane of line 4-4 of FIG. 3 and looking in the direction of the arrows; and

FIG. 5 is a somewhat simplified schematic illustration of the fuel metering system and associated regulating and adjusting means shown in FIGS. 1 through 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in greater detail to the drawings FIGS. 1 and 2 illustrate in top plan view and side elevational view, respectively, a multi-induction passage carburetor assembly having a body structure 12 which may be comprised of a main body section 14 with a lower disposed throttle body 16 and an upper air horn or air intake section 18 each of which is detachably secured to the main body section 14 as by any suitable means well known in the art.

The body structure 12, as shown, has induction passages 20, 22, 24 and 26 formed therethrough in a manner so as to form passages distinct from each other discharging into the intake manifold 28 of an associated internal combustion engine. For reference purposes, passages 20 and 22 are identified as being primary induction passages or bores while passages 24 and 26 are identified as being secondary bores. Accordingly, as such terms of reference imply, even through such is not necessary to the practice of the invention, the carburetor assembly 10 would be operated in a generally staged fashion. That is, throttle valves 30 and 32, each carried by a transversely located pivotal throttle shaft 34, are respectively located within primary induction passages 20 and 22. The throttle shaft 34, in turn, carries at one end thereof a throttle shaft a'ctuating lever 36 which is rotated in responce to operator demands so as to rotate such associated primary throttle vales in accordance therewith. Throttle valve 38 and 40, each carried by a secondary transversely extending throttle shaft 42, are respectively located within secondary passages 24 and 26. Similarly, throttle shaft 42 has an actuating lever 44 connected thereto; however, such lever 44 is operatively connected to the primary throttle shaft 34 through an intermediate linkage 46 which is connected to a third lever 48 fixedly secured to primary throttle shaft 34. Accordingly, as can best be seen in FIG. 2, opening rotational movement of the primary throttle shaft 34 causes a rotational throttle opening movement of secondary throttle shaft 42; however, because of the geometry of levers 44, 36, 48 and linkage 46, the rate of opening movement of the secondary throttle shaft 42, during the initial stages of opening, will be less than the rate of opening movement of the primary throttle shaft 34.

The primary induction passages 20 and 22 are provided with main venturi sections 50 and 52 within the throats of which are situated suitable main fuel discharge nozzles 54 and 56 as is well known in the art.

The air horn section 18 may include a primary air inlet section 58 which is defined generally by an upstanding wall 60 arranged in a generally rectangular configuration. A pivotal choke shaft 62 journalled in the wall 60 and carrying a choke valve 64 (shown in the fully opened position) may be operatively connected, as is well known in the art, to any suitable and related choke control mechanism whereby choke valve closure is effected at relatively cold engine and/or ambient temperatures.

In comparison, a second air inlet section, feeding the secondary induction passages 24 and 26, is defined generally by transversely extending wall surfaces 68 and 70 joined at their ends as by arcuate wall surfaces 72 and; 74 each of which, as shown, may be formed integrally within the air horn section 18. An air valve 76, having a top plan profile closely conforming to the configuration of the second air inlet section, is situated generally within the second air inlet and fixedly secured, as by screws 78, to a transversely extending air valve shaft which is suitable journaled in the wall section of the air horn 18 as at 82 of FIG. 2.

A suitably bridge-like portion 84, generally overlying the air valve 76, may be formed integrally with the air horn section 18. The bridge portion 84 may, as is well known in the art, contain a suitable spring-biased lever 85 which is operatively connected to either the air valve 76 or the air valve shaft 80 in order to thereby provide a minimal resilient force tending to maintain the air valve 76 in its nominally closed position as illustrated in FIG. 2.

As shown in FIG. 1, secondary fuel discharge nozzles 86 and 88 are provided for respectively discharging fuel into secondary induction passages 24 and 26. Accordingly, since the nozzles 86 and 88 are disposed generally below or beneath the air valve 76, suitable hood-like raised portions 90 and 92 are formed in the air valve 76 in order to provide sufficient space to accommodate the ends of nozzles 86 and 88 whenever air valve 76 is opened to or approaches its fully opened position.

A conduit 94, adapted for connection to a suitable source or supply of fuel, has its opposite ends 96 and 98 connected to fuel bowls or reservoirs 100 and 102 which, as shown, may be divorced from each other and formed integrally with the main body 14 so as to be disposed on opposite sides thereof. The cover portions for such fuel reservoirs may be formed integrally with the air horn 18 so as to form general lateral extensions 104 and 106 thereof.

As is generally well known in the art, air flow to the engine may be measured by the deflection of an air valve, such as 76, which is responsive to the volume rate of air flowing through the particular induction passage or passages containing the air valve. The air valve is then in turn operatively connected to a fuel metering valve whereby fuel flow to the engine will be regulated in accordance with the air flow and thus a proper mixture of air and fuel is delivered to the engme.

Accordingly, as can be seen in FIGS. 1, 2, 3 and 5, the air valve 76 is secured, in an offset manner, to shaft 80 for pivotal rotation therewith so that, as air impinges upon the larger offset area of the air valve 76, the air valve 76 causes clockwise (as viewed in FIG. 2) rotation of the shaft 80. In this connection, it can be further seen that ends 108 and 110 of shaft 80 extend into the chambers 112 and 114 of fuel bowls 100 and 102 and respectively carry cam assemblies 116 and 118 thereon. Also, the fuel bowls 100 and 102 are illustrated as being respectively provided with fuel metering valve assembly 120 and 122 situated generally within the chambers 112 and 114 thereof so as to be respec tively operatively connected to the cam assemblies 116 and 118 as by interconnecting lever means 124 and 126.

FIG. 3, is fragmentary a cross-sectional view taken on the plane of line-3 of FIG. 1; however, all elements shown therein are typical. That is, the disclosure as presented, for example, with reference to cam assembly 118, lever 126, metering valve 122, nozzle 88 and fuel bowl 102 apply equally well to the corresponding elements 116, 124, 120 86 and 102 as well as such structure as is related thereto.

Referring in greater detail to FIG. 3, it can be seen that the fuel metering valve assembly 122 is comprised of an outer generally tubular housing 130 having an open upperend 132 and an open lower end defining a conduit portion 134 which isalso provided with an externally threaded portion 136 which threadably engages an internally threaded portion 138 in the lower wall 140 of the fuel bowl 102. An elongated valve stem 142 situated generally within the housing 130 is provided with a lower tapered or contoured surface 144 which cooperates with an orifice 146 formed in a ringlike member 148 which, being of a relatively thin crosssection, can be snapped into a circumferential groove formed in the wall of conduit portion 134 or, if desired may be initially set onto a circumferential shoulder formed in the wall of conduit :134 and retained thereagainst as by peening over the portion immediately above it.

A second axially spaced shoulder serves to retain an annular spring abutment 150 for abutably engaging the lower end of a compression spring 152 which has its upper end engaging the lower surface of a moveable annular stop-guide 154 which is slidingly received within the cylindrical portion 156 of housing 130 while being press-fitted onto the cylindrical surface portion 158 of stem 1427 A third internally formed annular shoulder 160 may be formed to provide a positive stop or guaging surface against which the lower surface of collar-like guide 154 is at times abutted.

An upper annular member 162, which may be pressfitted on its outer diameter into the cylindrical surface 156, has an inner diameter 164 which slidably receives the cylindrical portion 158 of the valve stem therethrough. Suitable conduit means 166 are formed radially through the wall of outer housing 130 so as to be effective for freely converting or supplying fuel 168 from the chamber 114 of the fuel bowl 102 to the upstream side of metering orifice 146.

In view of the preceding, it should be apparent that as the valve stem 142 is depressed the effective flow or metering area of orifice 146 is decreased thereby reducing the volume rate of flow of fuel from passages 166 to the conduit 170 formed in the body 12 and communicating at its other end with a main fuelwell 172 which is effective for supplying fuel toonly one of the secondary nozzles 88. Likewise, as the valve stem 142 is permitted to rise, from the minimum flow position illustrated, the effective flow area of orifice 146 increased thereby enabling a greater volume rate of fuel flow therethrough and into the main well 172 feedin the nozzle 88.

The main well 172 may be provided with an elongated main well tube 174 which may be piloted as within an annular portion 176 and may be provided with a plurality of generally radially formed passages 178 communicating between the interior of the well 172 and the axial passageway 180, The upper end 182 of the main well tube 174 may be threaded so as to be threadably engageably with portion 184 of the air horn structure 18. A chamber 186, defined generally about the upper end of tube 174 and between threaded end 182 and annular portion 176, communicates with both the upwardly disposed radial passages 178a as well as a calibrated air vent or restriction 188. Accordingly, as is well known in the art, the purpose of such a main well tubeis to provide a controlled rate of air flow from the restriction 188 to the liquid fuel within main well 172 in order to create a partial mixing of such air and fuel prior to the discharge thereof through the fuel nozzle 88 into the induction passage 26.

Each of the cam assemblies, as typically shown by cam assembly 118 of FIGS. 3 and 4, is comprised of a main mounting bodyl have an aperture 192 formed therethrough and of a size so as to slidably and freely accept the end of air valve shaft 80 therethrough thereby permitting the cam mounting body to be freely rotatable with respect to the air valve shaft 80. A cam body 194, which may be formed integrally with mounting body portion 190, extends generally radially outwardly and has a peripheral contoured cam surface 196 which, as illustrated in FIG. 3, is adapted to be in contact with a follower portion 198 of the lever 126 pivotally secured at one end as at 202 to a suitable support portion 204 within the chamber 114 of the fuel bowl assembly 102.

As also shown in FIGS. 3 and 4, each of the cam assemblies, as 118, is provided with cam adjustment means 206 comprised of a body member 208 fixedly secured to the shaft 80 as by cooperating keying means comprised of, for example, a suitable flatted surface or surfaces 210 formed on shaft 80 and a complementary aperture 212 formed therethrough, the body 208 closely engaging such a flatted surface 210.

The body portion 208, which may be held to have its one side 214 against a shoulder 216 of shaft 80, is provided with a generally laterally extending arm portion 218 which has an internally threaded aperture 220 formed therethroughso as to threadably engage the externally threaded portion 222 of an adjustment member 224 provided with a suitable tool-engaging surface 226.

The adjustment member 224 is provided with a shank portion 228 carrying, at the lower end thereof, an enlarged ball key-like portion 230 which is closely slideably received within a cylindrical passageway 232 formed in the cam body 194. An elongated slot 234, open at its radially outermost end, serves to provide a clearance for the free passage therethrough of the shank or stem 228. Both fuel bowl cover portions 104 and 106 are provided with an internally threaded access aperture 236 for receiving a threaded cover or closure plug 238,

Accordingly, in view of the above, it should be apparent that, with the closure plug 238 removed, a suitable tool, such as a screw driver, may be inserted and engaged with surface 226 so as to threadably rotate adjustment member 224. If the adjustment member 224 is threadably rotated so as to cause ball portion 230 to move downwardly (as viewed in FIG. 4) cam body 194 and cam mounting portion 190 will rotate counterclockwise relative to and aboutshaft 80 (as viewed in FIG. 3). Such rotation of the cam body 194 is reflected in a downward force or movement against follower portion 198 causing lever 126 to rotate generally clockwise about pivot 202 resulting in lever end 240 further depressing fuel metering stem valve 142. Similarly, as adjustment member 224 is threadably rotated to cause ball 230 to move upwardly (as viewed in FIG. 4) the cam body 194 is caused to rotate clockwise relative to and about air valve shaft 80. This,

of course, permits spring 152 of the fuel metering valve assembly 122 to raise stem valve 142 against end 240 of lever 126 thereby maintaining follower portion 198 against the cam contour 196.

Accordingly, as somewhat schematically shown, in simplified configuration, in FIG. 5, with eachof the cam assemblies 116 and 118 being constructed in accordance with the disclosure of FIGS. 3 and 4 it becomes apparent that each of the cam assemblies 1 l6 and 118 can be independently adjusted relative to air valve shaft 80 and the air valve 76 fixedly carried thereby in order to achieve a very accurate control of the desired rate of flow of fuel through the respective fuel metering valve assemblies 120 and 122 for any particular deflection or operating position of the air valve 76, Further, not only are such cam bodies 194 of each of the cam assemblies 116 and 118 adjustable but they are also automatically and immediately locked into any adjusted position. This, of course, is achieved by virtue of the generally upper and lower surfaces of the ball 230 being to engage the cylindrical opening or slot 232 thereby precluding any movement of the cam body 194 which is not initiated by the adjustment member 224.

Even though only one preferred embodiment of the invention has been disclosed and described, it is apparent that other embodiments and modifications of the invention are possible within the scope of the appended claims.

I claim:

1. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, at least said first adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member being operatively connected to said cam body and being effective to cause adjustable rotation of said cam body relative to said air valve shaft means.

2. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member being operatively connected to said cam body and being effective to cause adjustable rotation of said cam body relative to said air valve shaft means and said air valve.

3. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enablingsaid air valve topivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, first and second lever members each including a cam follower portion respectively engaging said first and second adjustable cam means, each of said first and second lever members including valve engaging portions respectively engaging said first and second variably openable fuel metering valve assemblies, said first and second lever members being effective to respectively transmit motion developed by said first and second cam means upon rotation of said air valve in response to air flow through said induction passages to said first and second variably openable fuel metering valve assemblies.

4. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging inetered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source offuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel meteringlvalve' assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member comprising an adjustment body fixedly carried by said air valve shaft means, a threaded member threadably engaged with and carried by said adjustment body, said threaded member including a pivotal connecting portion operatively connected to said cam body at a point eccentrically disposed with respect to the axis of rotation of said cam body about said air valve shaft means, said pivotal connecting portion being effective to cause adjustable rotation of said cam body about said axis of rotation in response to adjustable threaded rotation of said threaded member in said adjustment body.

5. An air valve carburetor, comprising a carburetor body, a first inductionpassage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valye assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body freely mounted on said air valve shaft meansfor rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member comprising an adjustment body fixedly carried by said air valve shaft means, a threaded member threadably engaged with and carried by said adjustment body, said threaded member including a ball-like connecting portion, and said cam body including a key-like opening formed therein for closely receiving said ball-like connecting portion being effective to cause adjustable rotation of said cam body about said air valve shaft means in response to adjustable threaded rotation of said threaded member in said adjustment body.

6. An air valve carburetor according to claim 5, including first and second access openings formed in said carburetor body permitting the passage therethrough of suitable tool means for engaging and adjustably threadingly rotating each of-said threaded members.

7. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, said source of fuel comprising fuel bowl means carried by said carburetor body, each of said first and second variably openable fuel metering valve assemblies being situated within said fuel bowl means, each of said first and second adjustable cam eans being sitaiated within said fuel bowl means gmd irst and secon ever means situated within said uel bowl means, each of said lever means being pivotally connected to a support portion within said fuel bowl means and including a follower portion for respectively engaging said first and second adjustable cam means and a valve actuating portion for operatively respectively engaging said first and second variably openable fuel metering valve assemblies, each of said lever means being respectively effective to transmit motion generated by said first and second cam assemblies as a result of rotation of said air valve to said first and second variably openable fuel metering valve assemblies. 

1. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to saId air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, at least said first adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member being operatively connected to said cam body and being effective to cause adjustable rotation of said cam body relative to said air valve shaft means.
 2. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member being operatively connected to said cam body and being effective to cause adjustable rotation of said cam body relative to said air valve shaft means and said air valve.
 3. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel dischArge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, first and second lever members each including a cam follower portion respectively engaging said first and second adjustable cam means, each of said first and second lever members including valve engaging portions respectively engaging said first and second variably openable fuel metering valve assemblies, said first and second lever members being effective to respectively transmit motion developed by said first and second cam means upon rotation of said air valve in response to air flow through said induction passages to said first and second variably openable fuel metering valve assemblies.
 4. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body Freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member comprising an adjustment body fixedly carried by said air valve shaft means, a threaded member threadably engaged with and carried by said adjustment body, said threaded member including a pivotal connecting portion operatively connected to said cam body at a point eccentrically disposed with respect to the axis of rotation of said cam body about said air valve shaft means, said pivotal connecting portion being effective to cause adjustable rotation of said cam body about said axis of rotation in response to adjustable threaded rotation of said threaded member in said adjustment body.
 5. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first variably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, each of said first and second adjustable cam means comprising a cam body freely mounted on said air valve shaft means for rotation thereabout and relative thereto, and an adjustment member fixedly secured to said air valve shaft means for rotation therewith, said adjustment member comprising an adjustment body fixedly carried by said air valve shaft means, a threaded member threadably engaged with and carried by said adjustment body, said threaded member including a ball-like connecting portion, and said cam body including a key-like opening formed therein for closely receiving said ball-like connecting portion being effective to cause adjustable rotation of said cam body about said air valve shaft means in response to adjustable threaded rotation of said threaded member in said adjustment body.
 6. An air valve carburetor according to claim 5, including first and second access openings formed in said carburetor body permitting the passage therethrough of suitable tool means for engaging and adjustably threadingly rotating each of said threaded members.
 7. An air valve carburetor, comprising a carburetor body, a first induction passage formed through said body and including a first vAriably positionable throttle valve therein, a second induction passage formed through said body and including a second variably positionable throttle valve therein, a source of fuel, an air valve mounted within an inlet portion of said first and second induction passages so as to be responsive to the total volume of air flow through said induction passages, pivotal air valve shaft means fixedly secured to said air valve for enabling said air valve to pivotally deflect in relation to the volume rate of air flow through said induction passages, a first fuel discharge nozzle for discharging metered fuel into said first induction passage at a point generally downstream of said air valve but upstream of said first throttle valve, a second fuel discharge nozzle for discharging metered fuel into said second induction passage at a point generally downstream of said air valve but upstream of said second throttle valve, a first variably openable fuel metering valve assembly situated generally between said source of fuel and said first fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said first fuel discharge nozzle, a second variably openable fuel metering valve assembly situated generally between said source of fuel and said second fuel discharge nozzle for providing a metered rate of fuel flow from said source of fuel to said second fuel discharge nozzle, first adjustable cam means operatively connected to said air valve and said first fuel metering valve assembly effective for adjusting the degree of opening of said first fuel metering valve assembly relative to the position of said air valve, second adjustable cam means operatively connected to said air valve and said second fuel metering valve assembly effective for adjusting the degree of opening of said second fuel metering valve assembly relative to the position of said air valve, said source of fuel comprising fuel bowl means carried by said carburetor body, each of said first and second variably openable fuel metering valve assemblies being situated within said fuel bowl means, each of said first and second adjustable cam means being situated within said fuel bowl means, and first and second lever means situated within said fuel bowl means, each of said lever means being pivotally connected to a support portion within said fuel bowl means and including a follower portion for respectively engaging said first and second adjustable cam means and a valve actuating portion for operatively respectively engaging said first and second variably openable fuel metering valve assemblies, each of said lever means being respectively effective to transmit motion generated by said first and second cam assemblies as a result of rotation of said air valve to said first and second variably openable fuel metering valve assemblies. 